Daikin MPS040 F - Page 37

Ignition Control Module LED Diagnostics
The LED indicators (Table 21) can be used to diagnose faults associated with the modulating gas furnace.
Table 21: Modulating Ignition Control Troubleshooting Guide (UTEC 1171 Ignition Board)
LED Indicator System Status Fault Description Possible Causes and Corrective Action
Heartbeat System Normal N/A All conditions are normal
2 Flashes
Inducer ON
No gas
Combustion air ow pressure switch
contact is open; combustion inducer fan
is running
Pressure switch open with inducer ON
1. Combustion air ow pressure switch hose leaking; repair and/or replace
2. Combustion air ow pressure switch hose plugged; repair and/or replace
3. Combustion air ow pressure switch hose ttings plugged or damaged; repair
and/or replace
4 Combustion air pressure hose and/or switch has condensate accumulation;
repair and/or replace
5. Combustion air pressure switch not functioning; replace
6. Combustion inducer fan not working; repair or replace
3 Flashes No Flame
Combustion air pressure switch contact
is closed when fan is not running.
Pressure switch close with inducer ON
1. Check wiring to the combustion air ow pressure switch.
2. Check combustion air ow pressure switch continuity with OHM meter; if not
open replace
4 Flashes Lockout
Failed to ignite after too many failed
attempts
Lockout from too many failed ignition tries
1. Conrm gas supply available; verify manifold gas pressure is correct.
2. Verify manual gas shut-off valve is open.
3. Verify Gas Safety Control valve is in On position.
4. Conrm that spark is present. If not, check spark igniter for debris between
electrodes, cracked ceramic and damaged or disconnected wire connection.
Check ignition wire for cracks, coated with oil and debris.
5. Check for air leaks at inducer fan assembly and ue
6. Check for recirculation of exhaust ue gases.
7. If all above condition are OK, replace ignition board
5 Flashes Lockout
Burners light and then drop out resulting
in too many ame failures
Lockout from too many ame losses
1. Check ame sensor ceramic is not cracked; check ame rod for being coated
with debris and oil.
2. Check ame sensor wire is connected correctly; not cracked, no abrasions and
not covered with debris.
3. Check for recirculation of exhaust gases.
4. Check ame stability and proper location from sensor.
5. Check that pressure switch is not dripping due to loss of pressure.
6 Flashes No Flame
Inducer fan is running on high speed,
burners are OFF, high limit is open.
High temperature switch open
1. Check temperature rise and air ow over furnace heat exchanger
2. If high limit does not reset, change high limit switch
7 Flashes No Flame Rollout switch has tripped open
Rollout switch open
1. Check for blockages in exhaust vent assembly
2. Check for air leaks inside the burner compartment
3. Reset the Rollout switch and observe ame for any signs of rollout.
8 Flashes Lockout
Flame is present without any call for
heat
Flame present with gas OFF
1. Verify there is no voltage to the gas valve
2. Check gas line pressure making sure it is not higher than allowed by gas valve
manufacturer
3. If valve is not energized, check for gas ow. If gas is owing, replace gas valve;
verify line and manifold gas pressure are correct.
9 Flashes Lockout
Exceeded max limit trips in one call for
heat
Exceeded maximum limit trips in on call for heat (5)
oPTIonal Gas heaT
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